Screw conveyors have long been used for transferring product from one location to another. Typically, each conveyor comprises a cylindrical housing enclosing an auger mounted on an auger shaft. The housing has input and output ends for receiving and discharging product respectively. The auger shafts are rotatably driven at either the input or output end of the conveyor, depending upon the particular arrangement in which it is used.
Screw conveyors such as those just described are commonly found in farming operations for transferring grain from a grain wagon or truck to a storage facility, such as a silo, bin or crib. The conveyors are sometimes driven by a farm tractor using the power take-off, sometimes by an electric motor, and sometimes by an hydraulic motor, in turn driven by pressurized hydraulic fluid from the tractor hydraulic system. Presently available systems use a combination of two separate conveyors to do the transference of the grain. Thus, a first or delivery conveyor is driven by the power take-off of a tractor and transports grain directly into the storage facility. The first conveyor receives the grain at its input end from a second or feeder, usually much shorter, conveyor, that receives grain from a the wagon, for example, at its input end and discharges it at its output end into the input end of the first conveyor. In setups such as just described, the second conveyor has traditionally been driven by either an electric or an hydraulic motor. Electric motors have a somewhat limited usefulness in that the dual conveyor systems are sometimes used where electrical power is not available. Additionally, electric motors of an easily handled size are incapable of delivering the same level of power to the second conveyor that the first conveyor receives from the power take-off. Similarly, hydraulic motors require a power source having a large hydraulic capacity. Their use thus requires tractors of minimum size and prevents a farmer from adequately utilizing his equipment in other ways.
Dual conveyor systems where both conveyors are driven from a single power source such as a tractor power take-off are known. One of these systems, for example, drives the second conveyor from its output end via an attachment to the auger shaft of the first conveyor. A second known type drives the second conveyor from its output end via a connection between the second conveyor and the input end of the first conveyor. The first mechanical drive system just mentioned is not desirable in that the connective drive for the second conveyor lies within the path of the grain being dispensed from the second conveyor into the first conveyor. The second system is undesirable in that it requires assembly and disassembly of the connecting drive between the second conveyor and the first conveyor when it is desired to pivot the second conveyor to the other side of the first conveyor at a desired location for receiving grain.
It would be desirable to have a dual conveyor system driven by a mechanical drive system connected to a single power source that did not require substantial disassembly of the drive system when the angular position of the second, feeder conveyor was changed relative to the first conveyor and that was driven at the input end of each conveyor.